Roller-blind shutter.



J. GODDARD & F. F. DORSEY.

ROLLER BLIND SHUTTER;

APPLICATION FILED MAR.13, 1912.

Patented May 21; 1912.

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[lnwcenmmm s 1 COLUMBIA PLANOGRAPH C0., WASHINGTON. n. c.

UNITED STATES PATENT OFFICE.

JOSEPH GODDARD AND FARNUM F. DORSEY, OF ROCHESTER, NEW YORK, ASSIGNORS T0 SENECA CAMERA MANUFACTURING COMPANY, OF ROCHESTER, NEW YORK.

ROLLER-BLIND SHUTTER.

Specification of Letters Patent.

Application filed March 13, 1912. Serial No. 683,638.

To all whom "it may concern:

Be it known that we, Josnrrr GODDARD and FARNUM F. DORSEY, citizens of the United States, and residents of Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Roller-Blind Shutters, of which the following is a specification.

This invention relates to shutters of the type commonly designated as roller-blind shutters, in which a flexible curtaln is unwound from one roller, and rolled upon another roller, in the production of an exosure.

The object of the invention is to produce mechanism for cont-rolling the exposure-movement of a shutter of the type in question, this mechanism having simple and effective means for preventing the rebounding or recoiling action of the shutter-curtain, at the end of an exposure-movement, such as might result in a second accidental exposure.

In shutters of the type in question it 1s common to employ a roller, which may be designated as the primary roller, upon which the curtain or blind is normally rolled, the curtain, in the production of an ex posure, being drawn from the primary roller by the action of a secondary, spr ng-actuated roller, and its movement being controlled by an escapement-mechanism c0- operating with the primary roller. As such shutters are commonly designed to produce exposures of graduated lengths by the use of exposure-openings or slits of difierent widths, the escapement-mechanism is arranged to permit the curtain to be unwound from the primary roller sufliciently to cause one of the exposureopenings to pass across the focal plane, and to then arrest the movement of the curtain, this operation being repeated for each manual actuation of the escapement-mechanism. As the curtaln moves at high speed and must be suddenly arrested when so moving, it has been found that the escapement-mechanism and the primary roller have a tendency to rebound when the roller is suddenly arrested, so as to draw the curtain backwardly for a greater or less distance. To limit or prevent this rebound ing action and avoid a second exposure,such as might otherwise result therefrom, it has been proposed to employ a recoil-check or detent cooperating with the escapementmechanism. Such an arrangement is not completely effective, however, to prevent a recoiling action of the curtain, since the spring-actuated roller and the curtain tend to rebound or recoil, even when the upper rolleris held securely in its arrested position. In the present invention, however, we do not depend upon the escapementmechanism to prevent recoiling of the shutter, but employ instead a mechanism oooperating with the spring-actuated roller, this mechanism operating automatically to prevent any return movement of this roller at the end of an exposure movement. Accordingly, when the primary roller is suddenly arrested by the escapement-mechanism the spring-roller, under its momentum, rotates until arrested by the tension of the curtain, and then comes to rest without any rebounding movement. As the parts of the escapement-mechanism at this time are in full engagement the shutter is thus arrested with the curtain under tension and with no play or lost motion in any part of the mechanilsm which may permit the curtain to re- CO1 In the accompanying drawings :Figure 1 is a side-elevation of portions of a shuttermechanism embodying the present invent-ion, as seen from the inside of the shutter-casing; Fig. 2 is a rear-elevation of the same parts, showing also a portion of the casing in section; Fig. 3 is a view similar to Fig. 1, showing a modified form of the invention; and Fig. 4 is a vertical section, on a larger scale, showing in detail the parts immediately associated with the spring-roller.

While the present invention may be employed in connection with roller-blind shutters of various forms, it is illustrated, for convenience, as embodied in a shutter of which the general construction is disclosed in the patent to Joseph Goddard, No. 1,009,501, granted November 21, 1911, and the shutter is illustrated only in so far as is necessary for an understanding of the present invention.

In the illustrated embodiment of the invention the shutter is provided, as in said patent, with an upper primary curtain-roller 5, a lower spring-actuated roller 6, and a flexible curtain 7 which passes around guiderollers S, 8, from one curtain-roller to the other. The mechanism for actuating and controlling the curtain-rollers is mounted Patented May 21, 1912.

upon or connected with a plate fixed to the outer surface of the casing of the shutter at one side thereof.

The lower roller 6 is hollow and incloses a helical spring 10, as shown in Fig. 4. As in said patent, one end (not shown) of this spring is fixed to the roller 6, and the other end is fixed to a shaft 11, which projects through the plate 9. This shaft is normally stationary, but may be rotated in either direction, to adjust the tension of the spring, by means of adjListing-mechanism 12. This mechanism constitutes no part of the present invention and is not particularly illustrated and described.

As in said patent, the upper curtainroller 5 is provided with a pinion 13, which meshes with a gear 14, and this gear is connected with a manually-operable member 15, by which it may be rotated to wind the curtain upon the roller 5 and thus set the shutter.

The escapement-mechanism by which the primary curtain-roller is controlled is illustrated as similar to that in said patent. A pinion 16 meshing with the gear 14 is fixed to an arm 17 carrying a beveled lug 18. An escapement-lever 19 is pivoted on a stud 2O screwed into the plate 9, and this lever has an offset upper end 21. A fiat spring 22, fixed at its lower end to the escapementlever carries a beveled lug 23 at its upper end, and this lug normally engages the lug 18, as shown particularly in Fig. 2, thus preventing rotation of the gearing and the upper curtain-roller. The escapement-lever is normally held in the illustrated position by means of a spring 24, of which one end is fixed to a projection 25 on the escapementlever, and the other end is fixed to a screw 26 on the plate 9. By means of a button 27, projecting through an opening in the plate 9, the escapement-lever may be swung to the left of the position shown in Figs. 1 and 3, thus moving the lug 23 away from the lug 18. The tension of the curtain, due to the action of the spring-roller 6, then causes the primary roller 5 to rot-ate, and the arm 17 swings through a complete rotation, but is arrested at the end of such movement by the engagement of the lug 18 with the upper surface of a lug 28 formed at the upper extremity of the escapement-lever, this lug having been moved into operative position by the swinging of the escapement-lever as above described. The curtain is thus arrested at the end of an exposure-movement, as in said patent.

The present invention resides particularly in mechanism cooperating with the springroller 6. As shown in Fig. 4, a ratchetwheel 29 is fixed to the end of the'springroller. This ratchet may conveniently be made integral with the bushing 30 which closes the end of the roller. A detent-lever 31 is pivoted on a stud 32 below the escape ment-lever 19, and it carries, at its lower end, a spring-arm 33, which is adapted to co operate, in the manner of a pawl, with the ratchet 29. The upper end of the detent arm is slotted and engages a pin 34 projecting from the lower end of the escapementlever. In the normal position of the parts the spring 33 is out of engagement with the ratchet 29, so that it does not interfere with the rewinding of the curtain by means of the member 15, when it is desired to reset any portion of the curtain. hen the escapement-lever is moved as above described, however, to produce an exposure, the detent-lever 31 is swung, by its connection with the escapement-lever, so as to bring the spring 33 into operative engagement with the ratchet. During the succeeding exposure-movement the ratchet rotates freely in the direction of the arrow in Fig. 1, until the escapement-mechanism arrests the movement of the primary roller. The curtain, being then under tension, arrests the movement of the spring-roller, and the latter, owing to the elasticity of the curtain and of the escapement-mechanism, tends to rebound. This tendency is effectually resisted, however, by the spring 33 and the ratchet, and the shutter is thus brought to rest with the escapement-mechanism in the position in which it is arrested, and the curtain under tension, so that no recoiling of the curtain is possible.

A slightly modified form of the invention is illustrated in Fig. 3. In this construction a pawl 35 is pivoted near the axis of the spring-roller. For this purpose we may conveniently employ the stud 36 upon which is rotatively mounted the indicator-plate 37 which is employed, as in said patent, to in dicate the tension of the spring 10. A spring 38, engaging the pawl 35, tends to throw it into operative engagement with the ratchet 29. A lug 39 on the pawl is perforated to receive loosely the lower end of the wire 40. The upper end of this wire is pivoted to a lateral projection 41 on the escapement-lever, while the lower end passes through the lug 39 and is bent laterally. In the normal position of the parts the lower end of the wire engages the lower surface of the lug 39 and holds the pawl in raised position, and out of engagement with the ratchet, as shown in Fig. 3. When the escapement-lever is swung to the left, however, to produce an exposure, the wire 40 falls sufliciently to permit the pawl to swing downwardly into operative engagement with the ratchet, and the pawl then acts in the same manner-as the spring 33 of Fig. 1.

Both forms of the invention above de scribed are particularly adapted for use in connection with shutters of different sizes. In such shutters it is common to employ the same escapement-mechanism and the same spring-roller mechanism throughout, these mechanisms being simply situated at greater or less distances from each other according to the sizes of the shutters, and the length of. the plate 9 being governed accordingly. In adapting our novel detentmechanism to the different sizes of shutters it is necessary only, in one form, to change the length of the detent-lever 31' and the position of its fulcrum 32, or, in the other form, to vary the length of the wire and the invention may thus be applied to shutters of existing types without increase in their expense or complication.

Our invention is not limited to the em bodiment there'ot' hereinbefore described and illustrated in the accompanying drawings, but may be embodied in various other forms within the nature of the invention, as itis defined in the following claims.

We claim l. A photographic shutter having, in combination, a flexible curtain, a primary roller upon which the curtain is normally wound, a spring-actuated roller upon which the curtain is wound in producing an exposure, escapement-mcchanism cooperating with the primary roller to release and arrest the latter at the beginning and the termination of an exposure movement, and a detent operating automatically to prevent return movement of the spring-actuated roller when arrested, by the tension of the curtain, at the termination of an exposure movement.

2. A photographic shutter having, in combination, a flexible curtain, a primary roller upon which the curtain is normally wound, a spring-actuated roller upon which the curtain is wound in producingan exposure, escapement-mechanism cooperating with the primary roller to release and arrest the latter at the beginning and the termination of an exposure movement, a detent operating automatically to prevent return movement of the spring-actuated roller when arrested, by the tension of the curtain, at the termination of an exposure movement, and means for holding the detent normally in inoperative position.

3. A photographic shutter having, in combination, a flexible curtain, a primary roller upon which the curtain is normally wound, a spring-actuated roller upon which the curtain is wound in producing an exposure, escapement-mechanism cooperating with the primary roller to release and arrest the latter at the beginning and the termination of an exposure movement, a detent operating automatically to prevent return movement of the spring-actuated roller when arrested, by the tension of the curtain, at the termination of an exposure movement, and connections between the escapementmechanism and the detent for throwing the detent into operative position when the escapement-mechanism is moved to produce an exposure.

JOSEPH GODDARD. FARNUM F. DORSEY.

Witnesses:

MABEL L. HAOKETT, NELLIE A. BRANNIGAN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

